1. Background of the Invention
The present invention relates to the field of fluid handling, and more particularly pertains to an improved multiple pipette sampler system and related apparatus.
2. Description of the Prior Art
Pipettes of various configurations for withdrawing measured liquid samples from one container and transferring them to a second container have long been in use and are recognized as prior art. Typically, these pipettes require time-consuming care in achieving accurate measurement, and in their cleaning or sterilization between respective uses. Inaccuracies in measurements stem from lack of positive control of the shape and position of the liquid at the top and tip of the pipette at the time of filling, and also from variations in the amount of liquid left in the pipette tip upon expelling. Attempts to control these inaccuracies have in the past taken the form of costly manufacturing methods and the use of additional parts to control the filled liquid position, as well as the use of elaborate apparatuses to encourage uniform dispensing.
Advances in microbiological, immunological, and other statistical research methods have made individual sampling impractical in terms of time and cost. The requirement for large numbers of samplings of contaminating liquids has created a need for low cost, disposable, multiple pipette samplers. The prior art reveals a number of devices which represent attempts to solve the above-identified problems, and several multiple sample pipette assemblies are also in existence. Some of these devices are shown in U.S. Pat. Nos. 3,261,208, 3,568,735, 4,158,035, 4,461,328 and 4,468,974. A review of these patents will reveal that the attempts to provide accurate, multiple samples involve increased precision, materials, of numbers of parts--all of which add to the manufacturing cost and complexities. As such, it can be appreciated that the prior art attempts to control the uniformity of operation have resulted in awkward and time-consuming procedures and hardware.
As such, it appears that there is a continuing need for a multiple pipette sampler system which provides for a fast, convenient transfer of multiple liquid samples in repetitive situations wherein the construction thereof permits accurate sampling and minimum manufacturing cost, preferably in a disposable unit. In this respect, the present invention substantially fulfills this need.